1. Field of the Invention
The present invention relates to a vehicle having front and rear pairs of steerable driven wheels so constructed as to realize excellently small and stable turning.
2. Related Art
A vehicle shown in FIG. 5 of U.S. Pat. No. 6,336,513 B1 is provided at front and rear portions thereof with respective pairs of right and left steerable wheels. One pair of (rear) right and left steerable wheels are drive wheels supported by a transaxle housing so as to be driven by a prime mover provided on the vehicle through a transmission such as a hydrostatic stepless transmission (hereinafter, “HST”) disposed in the transaxle housing while they are turned laterally by steering operation. Furthermore, when the vehicle turns right or left, front and rear pairs of steerable wheels laterally turn symmetrically to each other with respect to a lateral line dividing the vehicle into front and rear portions. In this way, both the front and rear pairs of right and left steerable wheels are controlled in their lateral turning by steering operation, thereby enabling the vehicle to turn on an excellent small circle.
For traveling on rough or soft ground, a desirable feature for a vehicle having front and rear pairs of right and left wheels is to be able to transmit power to both the front and rear pairs of wheels. However, either the front or rear pair of steerable wheels of the above conventional vehicle, i.e., the wheels other than the pair supported by the transaxle housing are free from power of the prime mover. More specifically, there is no conventional vehicle provided at both front and rear portions thereof with respective pairs of right and left steerable wheels driven by the prime mover in association with steering operation.